% http://www.cs.kuleuven.be/~dtai/events/ASP-competition/Benchmarks/GraphColouring.shtml

:-include(base).

solve(As):-
    findall(V,member(node(V),As),Vs),
    findall(C,member(colour(C),As),Cs),
    findall(link(X,Y),member(link(X,Y),As),Es),
    map(Vs,Vars,MapV), % defined in base.pl
    map(Cs,0,ICs,MapC),
    Vars :: ICs,
    links_to_neqs(Es,Neqs,MapV),
    post_neqs(Neqs),
    labeling([ffc],Vars),!,
    map(CVs,Vars,MapC),
    output(Vs,CVs).
solve(_):-
    format("UNSATISFIABLE~n").
    
links_to_neqs([],[],_Map).
links_to_neqs([link(X,Y)|Es],[Vx#\=Vy|Neqs],Map):-
    map(X,Vx,Map),
    map(Y,Vy,Map),
    links_to_neqs(Es,Neqs,Map).

output([],[]):-nl.
output([V|Vs],[C|Cs]):-
    format("chosenColour(~w,~w). ",[V,C]),
    output(Vs,Cs).

test:-
    solve([node(1),node(2),node(3),link(1,2),link(2,1),link(2,3),link(3,2),link(3,1),link(1,3),colour(red),colour(green),colour(blue)]).